Digestive tract diseases are very common and in practice are most often expressed in the horse by signs of pain and discomfort called colic. In other cases, signs of digestive transit disturbance are observed, such as constipation or diarrhea, and more rarely, abdominal meteorism (translating a gaseous distension of a segment of the digestive tract). Finally, some conditions lead to swallowing disorders with hyper salivation. What causes colic? How to treat diarrhea? What are the effective remedies for colic in horses?
Understanding how the horse’s digestive system works to better understand colic
The anatomy of the digestive tract is quite complex. Ingested food is swallowed after mastication and goes into the stomach through the esophagus. The esophagus is equipped with a particular circular musculature in its distal portion, which prevents in this species any return of food to the mouth (vomiting is never observed). The stomach is a reservoir with a capacity of about 15 liters; its emptying is done permanently, and it is very rare that the stomach is completely empty. The small intestine is about 20 meters long and relatively mobile, attached to a large membrane attached to the sub lumbar vault, the mesentery. Its distal portion, the ileum, opens into a voluminous reservoir, the cecum (equivalent to the appendix in humans) which occupies a large part of the abdomen on the right. From the cecum starts the large intestine, whose ascending colon is folded on itself and thus includes ventral and dorsal, left, and right parts; these different portions, despite their size, can be mobile and move in the abdominal cavity. The terminal part of the digestive tract includes the transverse colon, the descending colon, and the rectum.
To this complex anatomy, and to better understand the different digestive disorders, we must add that the harmony of digestive transit and digestion are dependent on the one hand on digestive motricity, itself under nervous control, and on the other hand on the balance of the digestive flora and the absence of pathogenic elements causing parietal lesions such as viruses, bacteria, or parasites.
One cause of colic: esophageal obstruction
Esophageal obstruction is often seen in horses that eat too quickly, especially when the ration is distributed to several horses, including dominated horses that rush for food. It is also observed when coarse and/or highly fermentable feed is given, which causes a spasm and a stop in esophageal transit. The animal can no longer swallow but still makes efforts to swallow and salivates a lot; the congestion of its throat triggers a strong and very greasy cough. The major complication to be feared is false swallowing, i.e., the passage of non-swallowed food in the trachea which goes into the pulmonary territory and determines a bronchopneumonia whose consequences can be serious if it is not recognized and treated in time.
In case of esophageal obstruction, veterinary intervention is most often necessary: it consists of a catheterization with successive attempts to dislodge the blockage after administration of antispasmodics to decrease the contractions of the esophageal muscles, under sedation or general anesthesia, and sometimes if the extra-thoracic obstruction cannot be lifted, a surgical intervention can be lifesaving. More rarely, an esophageal malformation exists, and the occurrence of the obstruction reveals its existence. Colic refers to any abdominal pain expressed by the horse. It may be difficult at first to tell that the discomfort expressed by the horse is abdominal in origin, as some other musculoskeletal or respiratory conditions may be painful and therefore may produce the same symptoms. Even for the experienced clinician, it is not always easy to recognize a painful digestive condition and to differentiate it from an extra-digestive abdominal or extra-abdominal condition.
All about colic in horses
Pain of abdominal origin is expressed by the horse, according to its intensity but never according to its location, by the following symptoms: the horse scratches, has a worried face, lies down, sometimes rolls over, does not finish his ration, and sometimes sweats abnormally. In some cases of more severe pain, it is difficult to approach, sometimes throwing itself to the ground or against the walls of its stall in desperate cases. In more serious cases, a profound alteration of the general state of health associating despondency, prostration and advanced dehydration is observed. Sometimes, without necessarily corresponding to the primary disease, a decrease in the emission of droppings associated or not with abdominal meteorism is present. In the most serious cases, without medical intervention, the evolution towards a state of shock leading to death is possible.
Although colic in horses has been well known to the medical profession for a long time, its precise causes and means of prevention have not yet been fully understood. However, we do know that some horses are more prone than others, and that certain climatic factors can be incriminated as triggering or at least promoting factors. Undoubtedly, irregularity in work as well as in the distribution of meals and especially the level of parasite infestation contributes to the occurrence of these abdominal incidents which can turn into a drama. One of the essential mechanisms for the initiation of colic is an alteration in digestive motricity. Thus, the slightest spasm is likely to trigger a localized decrease in transit with distension of the digestive segment concerned, this distension leading to pain but also to other spasms in other digestive territories with the same repercussions. Moreover, such pathological phenomena can lead to momentary abnormalities in the position of certain portions of the digestive tract, but which can sometimes be definitive.
Therefore, colic in horses should be considered as a highly progressive condition requiring rapid veterinary intervention to identify as soon as possible the serious condition that warrants intensive medical treatment or even surgical treatment in a specialized center, or to treat a simple condition as soon as possible and prevent its evolution towards a complication.
The medical treatment is therefore based on analgesic substances but also on the support of the main functions and especially on the monitoring of the hydration state. However, it is advisable not to administer substances that are too powerful so as not to mask the evolution of the painful phenomenon, which allows the clinician to judge the seriousness of the condition and to opt for surgical treatment more quickly.
If the most frequent condition causing colic in horses is stasis in the pelvic curve (junction between two parts of the ascending colon), many other situations can be encountered and can only be recognized during a complete examination by a veterinarian during which he/she performs a palpation of the posterior abdomen by inserting the arm in the rectum of the horse. He can also, depending on the case, complete this examination by analyzing the abdominal fluid taken by puncture or by blood tests allowing him to appreciate the major organ functions.
After an initial examination, the decision to send the horse as soon as possible to a specialized center for intensive care or for surgical exploration of the abdomen can be taken and must always be prepared by those in charge of the horse so as not to lose this time which is precious for the prognosis of the surgical interventions to be the best possible. Even if these interventions have a certain cost, they allow, depending on the case and especially depending on how early they are taken care of, to provide therapeutic solutions with a good prognosis.
The implementation of medical care, sometimes intensive, is one of the elements of guarantee of success, even if the specific therapeutic act is surgical, the administration of perfusions to maintain correct hydration. Find out here how to prevent colic in horses.
Royal Horse H-150 is a forage supplement formulated for sustained effort, for horses and ponies prone to muscular and/or gastric dysfunction. Contains long-strand alfalfa fibers to promote salivation and limit gastric acidity.
Differentiating colic from diarrhea in horses
This is even more true for acute diarrhea in both foals and adult horses. In the latter, it is sometimes a digestive bacterial infection (such as salmonellosis) or a sudden proliferation of germs, usually present in the digestive tract but in small proportions, and this in different circumstances (stress such as transport, anesthesia, administration of certain drugs such as antibiotics …).
Acute diarrhea leads to dehydration, sometimes very fast and very important, requiring the administration of infusion solutions, the quantity of which is calculated according to the estimated dehydration (as an example, in case of moderate dehydration on a 500 kg horse, about 25 1 of infusion solution must be administered per day to cover the losses, without counting the maintenance needs)
Subacute or chronic diarrhea can also be observed in horses, requiring a particular and difficult diagnostic approach to find the cause. Most often the first cause invoked is parasitism, but there are others that are fortunately quite rare (liver diseases, infiltrative diseases of the digestive tract, digestive or abdominal tumors, peritoneal inflammation).
For more information: colic in horses
